THE MINERAL INDUSTRY of COLORADO This Chapter Has Been Prepared Under a Memorandum of Understanding Between the U.S

Gold

Crushed stone

Common clay

Cement plant

County boundary

Copper

Crushed stone/sand Capital City and gravel districts gravel and

Silver

Shale

Zinc

Concentration of mineral operations

Lead

Peat

Sulfur (oil)

Construction sand and gravel and

Dimension granite

Dimension sandstone

Dimension marble

Perlite plant

Sodium bicarbonate

Steel plant

Sodium carbonate

Gemstones Gypsum

Industrial sand Helium Molybdenum

Ag Au

Mo Zn

Clay

LEGEND

Cem

S-o

D-G

D-M

Per

Gyp

Peat

NaC

D-Sd

Gem

Steel

Nabic

MINERAL SYMBOLS MINERAL

(Major producing areas) producing (Major

1 PROWERS He

BACA

YUMA

PHILLIPS

SEDGWICK

Burlington

KIOWA Springfield

CHEYENNE

100 Kilometers 100

KIT CARSON KIT

BENT

LOGAN

WASHINGTON

LINCOLN

OTERO

CROWLEY

MORGAN

LAS ANIMAS

ELBERT

ARAPAHOE

Clay

Pueblo 2

WELD

ADAMS

Clay

Steel

EL PASO EL

PUEBLO

Colorado Springs

Denver

Clay

Peat

Clay

DENVER

S-o

DOUGLAS

HUERFANO

AuAg

Cem Boulder

JEFFERSON Gem

TELLER

Gyp

Clay

Cem

Clay

D-Sd

D-G CUSTER

Fort Collins Fort

COSTILLA

Gem BOULDER

Cripple Creek Cripple

GILPIN

CLEAR CREEK

LARIMER

PARK

FREMONT

Mo ALAMOSA

COLORADO

Gem

Leadville

SUMMIT

CONEJOS

CHAFFEE

GRAND

Per

LAKE

SAGUACHE

JACKSON

Gyp

RIO GRANDE RIO

EAGLE

PITKIN

MINERAL

ROUTT

GUNNISON

D-M

ARCHULETA

HINSDALE

Au, Ag, Cu, Pb, Zn Pb, Cu, Ag, Au,

SG SAN JUAN SAN

OURAY

LA PLATA LA

DELTA

Silverton

Durango

GARFIELD

MOFFAT

NaC

Nabic

RIO RIO BLANCO

MESA

MONTROSE

SAN MIGUEL SAN

DOLORES

MONTEZUMA Grand Junction Grand Source: Colorado Geological Survey/U.S. Geological Survey (2003) Survey Geological Survey/U.S. Geological Colorado Source: THE MINERAL INDUSTRY OF COLORADO This chapter has been prepared under a Memorandum of Understanding between the U.S. Geological Survey and the Colorado Geological Survey for collecting information on all nonfuel minerals.

In 2003, the estimated value1 of nonfuel mineral production 10th in gypsum and decreased to 10th from 8th in construction for Colorado was $673 million, based upon preliminary U.S. sand and gravel. Additionally, Colorado produced significant Geological Survey (USGS) data. This was a 6% increase from quantities of portland cement, crushed stone, dimension stone, that of 20022 and followed a more than 17% increase from 2001 and gemstones (11th based on value). to 2002. The State increased to 22d from 23d in rank among The following narrative information was provided by the the 50 States in nonfuel mineral production value, of which Colorado Geological Survey3 (CGS) much of the data is based Colorado accounted for more than 1.5% of the U.S. total. on its own surveys, estimates, and information gathered from The State’s two leading nonfuel mineral commodities in company annual reports. 2003, by value, were construction sand and gravel and portland cement, followed by gold, molybdenum concentrates, and Exploration and Development Activities crushed stone (third in 2002). Significant increases took place in the production and values of all metals in 2003 in contrast Constellation Copper Corp. conducted exploratory drilling to small decreases in the two aggregate commodities; portland in 2003 on the Cashin copper deposit in Montrose County near cement was up, slightly. In 2003, about 30% of Colorado’s the Utah border. Cashin is located 24 kilometers northeast of nonfuel mineral production value resulted from the production Constellation’s Lisbon Valley copper deposit in Grand County, of metals—gold, molybdenum concentrates, and silver—in Utah. The Cashin deposit is considered a satellite of the Lisbon descending order of value; this was a significant increase from Valley deposit and may eventually provide ore feed to the the 23% of 2002. planned processing facilities at Lisbon Valley. Copper was In 2002, Colorado’s rise in value was led by increases in the originally discovered in the Cashin area in 1896 and was mined production and related values of molybdenum concentrates from 1899 to the mid-1900s. Historic mining in the Cashin area and construction sand and gravel, up about $30 million and focused on high-grade deposits along steeply dipping, northeast- $28 million, respectively, and a substantial rise in those of soda trending faults. Mineralization consists principally of the ash, up about $13 million, and gold. Additionally, significant copper carbonates, malachite, and azurite. Chalcocite, neoticite, increases also took place in crushed stone, up $7.7 million, and and chrysocolla are also present. Native copper (and some cement (portland and masonry), up nearly $4 million. Relative native silver) was occasionally found in the high-grade parts of to these, most other nonfuel minerals showed significantly the historic mine. Copper mineralization at Cashin is hosted smaller changes in value, for the most part small decreases, that by the Wingate Sandstone of Triassic age. Based on previous were inconsequential to the net result for the year (table 1). drilling, a mineral inventory of approximately 12 million metric Compared with USGS estimates of the quantities produced tons (Mt) grading 0.5% copper (130 million pounds of copper) in the other 49 States during 2003, Colorado remained second was estimated for Cashin prior to the 2003 exploration program. in rank in molybdenum concentrates, third of 3 States that Much of the 2003 drilling targeted areas had never previously produce soda ash, and fifth in gold. The State rose to 8th from been tested. Assay results released by Constellation suggest that the drilling was successful in delineating additional copper 1The terms “nonfuel mineral production” and related “values” encompass mineralization, as well as upgrading the resource that was variations in meaning, depending upon the mineral products. Production may partially defined by previous exploration. be measured by mine shipments, mineral commodity sales, or marketable Calais Resources conducted exploration drilling at its production (including consumption by producers) as is applicable to the individual mineral commodity. Consolidated Caribou project in Boulder County in late 2003, All 2003 USGS mineral production data published in this chapter are the highlight of which was a 1,108-meter (m) core-drilling preliminary estimates as of July 2004 and are expected to change. For some program (The Mining Record, 2004). Several previously mineral commodities, such as construction sand and gravel, crushed stone, and untested gold-bearing veins were encountered in the drilling. portland cement, estimates are updated periodically. To obtain the most current information, please contact the appropriate USGS mineral commodity specialist. Calais Resources announced that the company expected to Specialist contact information may be retrieved over the Internet at URL http:// commence a 20,000-m core-drilling campaign in April. The minerals.usgs.gov/ minerals/contacts/comdir.html; alternatively, specialists’ Consolidated Caribou project is located within the northeast- names and telephone numbers may be obtained by calling USGS information trending Colorado Mineral Belt. Mineralization is hosted at (703) 648-4000 or by calling the USGS Earth Science Information Center at 1-888-ASK-USGS (275-8747). All USGS Mineral Industry Surveys and USGS Minerals Yearbook chapters—mineral commodity, State, and country—also may 3John W. Keller, a geologist at the Colorado Geological Survey, authored the be retrieved over the Internet at URL http://minerals.usgs.gov/minerals. text of the State mineral industry information provided by that agency. 2Values, percentage calculations, and rankings for 2002 may differ from the Minerals Yearbook, Area Reports: Domestic 2002, Volume II, owing to the revision of preliminary 2002 to final 2002 data. Data for 2003 are preliminary and are expected to change; related rankings also may change.

COLORADO—2003 8.1 mainly by northeast- and east-west-striking quartz veins and Cretaceous), the Dakota Sandstone (Lower Cretaceous), and the breccia zones. Country rock consists of Proterozoic age gneiss Dawson Formation (Upper Cretaceous to Tertiary). Elsewhere and granodiorite that have been cut locally by Tertiary age in the State, clay deposits within the Lykins, Morrison, Benton, intrusives, principally monzonite and quartz monzonite. A study Niobrara, Mesaverde and Vermejo Formations (ranging in age by Calais Resources in 1998 indicated combined resources of from Triassic to Cretaceous) have also been exploited. 1.3 Mt of ore containing more than 13,000 kilograms (kg) of The Pierre Shale in northern Jefferson County is mined by gold (10 grams per metric ton) and 364,000 kg of silver (280 Texas Industries, Inc. for use as lightweight aggregate. The grams per metric ton). Also, there are recoverable quantities mined shale is kiln-fired to the point where it expands in size of lead, zinc, and copper in the ore. Geologic modeling that and becomes low in density and weight. Lightweight aggregate incorporates new drill data and updated interpretations of is used in place of regular sand, gravel, or crushed stone in historic geologic data, using sophisticated three-dimensional applications where excessive weight is undesirable, such as modeling software, is continuing. floors and walls in multistory buildings. Cinder blocks are In early 2003, Hinsdale County Commissioners approved a commonly made with lightweight aggregate. plan of mining operations for Midas Mining Co. (also known Crushed Stone and Sand and Gravel.—The largest segment as Ophir-Nevada Mining Co.) to reopen the Ophir Lode, a of the nonfuel mineral industry in Colorado continued to be historic gold, silver, and base-metal mine in the Henson Creek crushed stone and sand and gravel. Colorado produced nearly mining district near Lake City in the San Juan Mountains. The 49.9 Mt of aggregate in 2003 and ranked 10th in the Nation county stipulated that a maximum of six truckloads of ore per for sand and gravel production. The total value of Colorado day could be transported out of the mine site via public roads. aggregate produced was $292 million. This was a decrease of The trucks must be no larger than 10-wheel tandem dump 9% below the 2002 value of $319 million. Sand and gravel trucks. When operational, the company expects this small-scale represent 66% of Colorado’s total aggregate production, and operation to produce about 6,400 metric tons (t) of ore per year, while sand and gravel production totaled nearly 37 Mt, it was operating seasonally. The mined ore will not be processed at down 17% from last year’s production. Similarly, crushed stone the mine site. The company received its mining permit from production decreased 9%. Average unit values of $5.51 and the Colorado Division of Minerals and Geology in 2003. As of $6.40 per metric ton were calculated for sand and gravel and March 2004, mining had not yet begun at the site. crushed stone, respectively. The top uses for sand and gravel are concrete aggregate, road base and coverings, construction Commodity Review fill, and asphaltic concrete aggregate. Crushed stone is used primarily as an aggregate for road construction and highway Industrial Minerals maintenance. Dimension Stone.—The Yule quarry is operated by Sierra Cement.—The Portland Plant near Florence is operated by Minerals Corp. In 2003, the Yule quarry produced 699 cubic Holcim (US), Inc. Cement is produced using the dry method in meters (1,900 t) of world-renowned white marble. This its processing plant, which has a capacity of 1.7 million metric represents a significant decrease of about 45% from that of tons per year. In 2003, the plant produced slightly more than 2002. The number of employees at the quarry decreased from 1.1 Mt of cement, employed about 180 people, and has not lost 13 to 7. The bulk of the quarried stone is used for sculpting, production time to accidents in 500 days. The majority of its national cemetery headstones, and monuments, although product is used in the metropolitan Denver area and throughout recently, slab and tile stone production has been on the rise. In Colorado; some cement is also distributed to western Kansas 2002, Sierra was awarded a contract to cut a massive block of and Nebraska. Limestone from the Fort Hays Member of marble to replace the cracked Tomb of the Unknown Soldier the Niobrara Formation of Upper Cretaceous age is mined by in Washington, DC (original carved from Yule marble in Holcim as the principal raw ingredient for its cement. The 1931). Two blocks have already been cut, but both proved Codell Sandstone, also of Cretaceous age, is mined for use as a to be imperfect, so mining crews are searching the quarry for silica additive. yet another suitable block, which they hope to have cut by the Portland and masonry cement are produced at the CEMEX summer of 2004. Other structures using Yule marble include mine and processing plant near Lyons in Boulder County. the Lincoln Memorial, the Colorado State Capitol and Annex The plant uses the dry-processing method and employs about buildings, and Denver International Airport. The majority of the 100 people. Cement production in 2003 was 467,000 t, most Yule marble is marketed under the name Colorado Yule Marble. of which was used in the greater metropolitan Denver area. Very high-quality stone shipped to Italy is marketed under the Cement ingredients (limestone and shale) are mined locally name Sierra White. from the Niobrara Formation and the overlying Pierre Shale. A relatively small operation, the Colorado Red Rose Clay and Shale.—Common clay is mined in eastern quarry produced blocks of red granite for use as countertops, Colorado, especially near the Front Range in Jefferson, Elbert, monuments, and building stone. Annual production from the Douglas, El Paso, Pueblo, and Fremont Counties. In 2003, quarry is about 900 t, most of which is sold in Colorado. The mines in Colorado produced a total of 214,000 t of common Red Rose quarry uses an innovative technique to cut the stone. clay, the same as in 2002. The value of this clay was estimated Having tried unsuccessfully to use traditional methods, the at $1.26 million. In eastern Colorado, clay is mined principally quarry founder invented and patented an automated water jet from three formations: the Laramie Formation (Upper

8.2 U.S. GEOLOGICAL SURVEY MINERALS YEARBOOK—2003 channeler, which uses a very small stream (the size of a pencil the Green River Formation. American Soda LLP (formerly a lead) of highly pressurized water to erode the stone crystal subsidiary of Williams Companies) was acquired by Solvay by crystal. The channeler may be used either horizontally or America, Inc. in September 2003. The company controls more vertically and improves both the speed and quality of production than 1,800 hectares (ha) of mineral leases on U.S. Bureau of and may be run unattended. A typical block (about 3 x 1.7 x Land Management (BLM) land. The estimated in situ nahcolite 0.9 m) may be cut (channeled) on all four sides and removed resource is 3.2 billion metric tons, with more than 900 Mt of from the deposit using plugs and feathers in less than 2 days. recoverable nahcolite. Colorado Rose Red celebrated 20 years of water jet channeling In February 2003, White River Nahcolite was purchased in 2002. for $20.6 million by Natural Soda AALA, Inc. (a subsidiary Sandstone continued to be quarried in several places in of AmerAlia, Inc.). In 2003, the plant produced about 70,000 Colorado, especially along the base of the Front Range in t of sodium bicarbonate. High-grade nahcolite (more than Larimer and Boulder Counties. The Permian age Lyons 80%) was recovered from the “Boise Bed” of the Green River Sandstone is quarried in flat slabs and used as building stone, Formation—a bed that was not present at the American Soda walkway stone, and decorative wall facing. The Cretaceous age LLC plant. Dissolution of the nahcolite was through horizontal Dakota Sandstone is quarried for similar uses in several places drill holes along the base of the Boise Bed. The mine’s designed around the State. Alabaster is quarried from the Permian age capacity was 113,000 metric tons per year. Both food-grade and Lykins Formation at a small mine near Fort Collins by Colorado industrial-grade products were produced. Natural Soda, Inc. Alabaster Supply. In 2003, the company produced just under also owns the Rock School Lease, an undeveloped nahcolite 180 t of stone. Its alabaster is used mainly for sculpting and property nearby. The two properties, both leased from the BLM, is marketed both locally and nationwide. The White Banks together comprised more than 3,800 ha in the Piceance Creek mine in Pitkin County also produced alabaster, as well as basin. These leases contain in situ nahcolite resources estimated dark-colored marble, and quartz. The Eocene age Castle Rock to exceed 3.6 billion metric tons. rhyolite is quarried by the Ames Construction Company near the town of Castle Rock. Metals Gypsum.—Centex Construction Products Inc.’s American Gypsum operation produced 535,000 t of gypsum in 2003 Gold, Silver, and Base Metals.—The Cripple Creek & Victor from its mine in the town of Gypsum. This represents about Gold Mining Co. (CC&V) continues to operate the only large a 7% increase in production compared with that of 2002. The precious-metal mine in Colorado. The Cresson Mine in Teller company is in the process of developing a new mining area County produced about 8,830 kg of gold in 2003, up 27% from northeast of the current site. During a span of a few years, the nearly 6,970 kg produced in 2002. The increase is due to mining will shift to the new area as reserves are depleted in the the October 2002 completion of a major expansion and capital original site. The future mining area ensures that the wallboard improvement project. The project included a fleet of nine plant in the town of Gypsum can operate for at least another 20 280-t Euclid Hitachi EH 4500 haul trucks, an expanded heap- years. Approximately 56 million square meters of wallboard are leach pad, construction of a new maintenance facility, a new manufactured at the plant per year. About 50% of the wallboard crushing facility, and an expanded gold recovery plant. Gold goes to the Colorado construction industry, and the remainder prices increased substantially in 2003, averaging $363 per ounce 4 is marketed throughout the United States. The mine and plant according to Kitco, Inc. (2004§ ). This is an 18% increase employ approximately 120 people. The bedded gypsum deposit from the 2002 average gold price of $310 per ounce. The CGS is within the Eagle Valley Formation evaporite sequence of estimates that the raw value of the gold produced at the mine Pennsylvanian age. in 2003 was approximately $103 million. Silver was produced Colorado Lien (a subsidiary of Pete Lien & Sons, Inc. of as a byproduct at the mine as well. In 2003, about 4,420 kg of South Dakota) produced gypsum from the Munroe quarry silver was produced. The raw value of silver produced is less north of Fort Collins near Livermore. Gypsum is extracted than 1% of the gold. Production at the mine is expected to again from the Permian Lykins Formation using a portable crusher. increase in 2004 to an estimated 11,000 kg of gold as benefits Annual production averages about 45,000 t. The majority of the and efficiencies of the earlier expansion are fully realized. The material quarried is sold within the State to the cement industry. current reserve base is sufficient to support gold production until Soda Ash.—Colorado soda ash and sodium bicarbonate 2012. CC&V is a joint venture between AngloGold and Golden are derived from nahcolite, a naturally occurring sodium Cycle Gold Corp. The mine currently employs approximately bicarbonate mineral that is present in large quantities in the 300 people and is the largest private employer in Teller County. sedimentary rocks of the Piceance basin in northwestern The Pride of the West Mill northeast of Silverton in San Juan Colorado. The nahcolite is disseminated in oil shale of the County has been rehabilitated to process base-and precious- Eocene age Green River Formation at depths of about 610 to metal ore derived from historic mine waste piles in the Animas River watershed. The project is managed by the Silver Wing 760 m below the surface It is estimated that 29 billion metric . Co., Inc. of Silverton, Colorado. In February 2003, the project tons of nahcolite are present within the Piceance Creek basin. In 2003, American Soda shipped 500,000 t of soda ash and 85,000 t of sodium bicarbonate, slightly more production than 4A reference that includes a section mark (§) is found in the Internet that of 2002. Nahcolite is solution mined from 25 to 30 vertical Reference Cited section. wells that penetrate several nahcolite-rich oil shale beds of

COLORADO—2003 8.3 received final approval from the State to begin processing official State Rock. The Governor signed this bill into law in material. In August 2003, the mill began processing ore. March 2004. The addition of the white Yule Marble completes Concentrates have been produced but have not been shipped Colorado’s patriotic theme of red (State Mineral, rhodochrosite), yet. Extreme cold weather and a lack of insulating snow cover white, and blue (State Gemstone, aquamarine). in November 2003 resulted in the mill “freezing up,” and it The CGS released a new digital publication entitled was shut down for the rest of the winter. The Pride of the West “Directory of Active and Permitted Mines in Colorado—2002.” Mill has strong support and assistance from the Animas River This CD-ROM contains information on each mine and quarry in Stakeholders Group (its Web site is located on the Internet at Colorado including commodity, location, mine operator contact URL http://www.waterinfo.org/arsg/main.html), a coalition of information, production information (where available), and private, State, and Federal interests that are working to clean up basic geology. A high-quality color shaded-relief map showing mine waste that contributes to the pollution of the Animas River. the mine locations, highways, cities and towns, railroads, and The Golden Wonder is a small, underground gold mine about other features is included on the CD-ROM. The directory lists 2 miles southeast of Lake City in Hinsdale County. High-grade the operating mines in the State as well as mines that have gold ore was mined from epithermal quartz veins. The ore was valid, active permits from the Colorado Division of Minerals trucked out of State in “super sacks” for milling and further and Geology but operate only sporadically or were otherwise processing. No quantitative information regarding production temporarily closed at the time of this investigation (Guilinger for this mine is publicly available. and Keller, 2004). Additionally, the CGS completed fieldwork Molybdenum.—The Henderson Mine in Clear Creek County for seven new 1:24,000-scale geologic maps as part of the continued to be North America’s largest primary producer of STATEMAP component of the National Cooperative Geologic molybdenum. The underground mine is owned by Climax Mapping Program. A complete listing of publications available Molybdenum Co. (a subsidiary of Phelps Dodge Corp.). The from the CGS can be found on the Internet at URL http:// operation employed about 320 workers at the mine and mill. geosurvey.state.co.us/. In 2003, the mine and mill produced 10,100 t of molybdenum metal contained in concentrates. That is about an 8% increase References Cited from the 9,300 t produced in 2002. In 2003, the estimated average price for molybdenum contained in technical-grade Guilinger, J.R., and Keller, J.W., 2004, Directory of active and permitted mines molybdic oxide was $5.33 per pound, up 42% from an average in Colorado—2002: Colorado Geological Survey Information Series 68, of $3.75 in 2002. Using the average price, the calculated value CD-ROM. of molybdenum produced at the Henderson Mine in 2003 was Mining Record, The, 2004, Calais active on three gold district properties: The Mining Record, v. 115, no. 1, January, p. 5. estimated to be $119 million. Internet Reference Cited Government Programs Kitco, Inc., 2004, Gold 2003, accessed April 6, 2004, at URL http://www.kitco. Late in 2002, a Denver-area Girl Scout troop began a com/scripts/hist_charts/ yearly_graphs.cgi. campaign to create a bill to make Colorado Yule Marble the

8.4 U.S. GEOLOGICAL SURVEY MINERALS YEARBOOK—2003 TABLE 1 NONFUEL RAW MINERAL PRODUCTION IN COLORADO1, 2

(Thousand metric tons and thousand dollars unless otherwise specified)

2001 2002 2003p Mineral Quantity Value Quantity Value Quantity Value Clays, common 254 1,500 214 1,260 214 1,260 Gemstones NA 269 NA 269 NA 274 Gold3 kilograms 6,660 58,300 W W W W Lime 33 2,000 20 1,250 20 1,320 Sand and gravel: Construction 37,300 194,000 40,700 222,000 37,000 204,000 Industrial W W 61 W 63 W Silver3 kilograms 2,830 399 W W W W Stone: Crushed 13,800 r 88,300 r 15,000 96,000 13,600 88,400 Dimension 11 2,130 18 2,400 17 2,050 Combined values of cement, clays [bentonite, fire (2000)], gypsum (crude), helium (Grade-A), molybdenum concentrates, soda ash (2001-02), stone [dimension marble and sandstone (2000)], and values indicated by symbol W XX 193,000 XX 311,000 XX 376,000 Total XX 540,000 r XX 634,000 XX 673,000 pPreliminary. rRevised. NA Not available. W Withheld to avoid disclosing company proprietary data; value included with "Combined values" data. XX Not applicable. 1Production as measured by mine shipments, sales, or marketable production (including consumption by producers). 2Data are rounded to no more than three significant digits; may not add to totals shown. 3Recoverable content of ores, etc.

TABLE 2 COLORADO: CRUSHED STONE SOLD OR USED, BY KIND1

2001 2002 Number Quantity Number Quantity of (thousand Value Unit of (thousand Value Unit Kind quarries metric tons) (thousands) value quarries metric tons) (thousands) value Limestone 10 4,820 $30,900 $6.40 11 4,620 $30,900 $6.68 Dolomite 1 W W 4.63 1 W W 4.63 Granite 8 4,310 29,200 6.78 7 3,970 26,800 6.76 Traprock 1 W W 3.79 1 W W 4.18 Sandstone and quartzite 8 1,780 10,900 6.12 9 2,770 16,100 5.82 Volcanic cinder and scoria 1 r W W 3.58 r 1 W W 3.86 Miscellaneous stone 16 2,360 15,100 6.42 11 3,070 20,000 6.51 Total or average XX 13,800 r 88,300 r 6.38 XX 15,000 96,000 6.42 rRevised. W Withheld to avoid disclosing company proprietary data; included in "Total." XX Not applicable. 1Data are rounded to no more than three significant digits, except unit value; may not add to totals shown.

COLORADO—2003 8.5 TABLE 3 COLORADO: CRUSHED STONE SOLD OR USED BY PRODUCERS IN 2002, BY USE1

Quantity (thousand Value Unit Use metric tons) (thousands) value Construction: Coarse aggregate (+1 1/2 inch): Riprap and jetty stone 115 $1,100 $9.54 Other coarse aggregates 53 225 4.25 Total or average 168 1,320 7.87 Coarse aggregate, graded: Concrete aggregate, coarse 44 281 6.39 Bituminous aggregate, coarse 517 3,850 7.44 Bituminous surface-treatment aggregate W W 4.18 Railroad ballast W W 4.37 Total or average 604 4,310 7.14 Fine aggregate (-3/8 inch): Stone sand, bituminous mix or seal 496 2,080 4.19 Screening, undesignated (2) (2) 3.31 Coarse and fine aggregates: Graded road base or subbase 137 503 3.67 Unpaved road surfacing 46 282 6.13 Terrazzo and exposed aggregate W W 4.65 Crusher run or fill or waste W W 3.53 Total or average 458 1,760 3.83 Other construction materials 75 624 8.32 Agricultural: Limestone (3) (3) 27.56 Poultry grit and mineral food (3) (3) 24.52 Other agricultural uses 129 2,820 21.87 Total or average 129 2,820 21.87 Chemical and metallurgical, cement manufacture (2) (2) 4.52 Special: Mine dusting or acid water treatment (2) (2) 29.10 Asphalt fillers or extenders (2) (2) 21.42 Other miscellaneous uses: Specified uses not listed 20 95 4.75 Glass manufacture (2) (2) 19.40 Unspecified:4 Reported 10,900 69,100 6.36 Estimated 1,100 7,300 6.48 Total or average 12,000 76,400 6.37 Grand total or average 15,000 96,000 6.42 W Withheld to avoid disclosing company proprietary data; included in "Total." 1Data are rounded to no more than three significant digits, except unit value; may not add to totals shown. 2Withheld to avoid disclosing company propreitary data; included in "Grand." 3Withheld to avoid disclosing company proprietary data; included with "Other." 4Reported and estimated production without a breakdown by end use.

8.6 U.S. GEOLOGICAL SURVEY MINERALS YEARBOOK—2003 TABLE 4 COLORADO: CRUSHED STONE SOLD OR USED BY PRODUCERS IN 2002, BY USE AND DISTRICT1, 2

(Thousand metric tons and thousand dollars)

District 1 District 2 District 4 Use Quantity Value Quantity Value Quantity Value Construction: Coarse aggregate (+1 1/2 inch)3 WWWWWW Coarse aggregate, graded4 W W -- -- W W Fine aggregate (-3/8 inch)5 ------W W Coarse and fine aggregate6 WWWWWW Other construction materials 32 280 34 313 -- -- Agricultural7 -- -- W W -- -- Chemical and metallurgical8 -- -- W W W W Special9 -- -- W W -- -- Other miscellaneous use10 ------Unspecified:11 Reported 266 1,410 -- -- 9,630 62,600 Estimated 30 170 330 1,600 230 1,300 Total 397 2,450 689 7,210 11,600 73,500 District 5 District 6 Unspecified districts Quantity Value Quantity Value Quantity Value Construction: Coarse aggregate (+1 1/2 inch)3 71 499 ------Coarse aggregate, graded4 38 198 ------Fine aggregate (-3/8 inch)5 W W ------Coarse and fine aggregate6 WW 6 33 -- -- Other construction materials 9 31 ------Agricultural7 W W ------Chemical and metallurgical8 ------Special9 W W ------Other miscellaneous use10 W W ------Unspecified:11 Reported 933 4,890 (12) (12) 33 201 Estimated 530 4,200 7 36 -- -- Total 2,190 12,600 13 70 33 201 W Withheld to avoid disclosing company proprietary data; included in "Total." -- Zero. 1Data are rounded to no more than three significant digits; may not add to totals shown. 2No production for District 3. 3Includes riprap and jetty stone and other coarse aggregates. 4Includes bituminous aggregate (coarse), bituminous surface-treatment aggregate, concrete aggregate (coarse), and railroad ballast. 5Includes stone sand bituminous mix or seal and screening (undesignated). 6Includes crusher run (select material or fill), graded road base or subbase, terrazzo and exposed aggregate, and unpaved road surfacing. 7Includes agricultural limestone, poultry grit and mineral food, and other agricultural uses. 8Includes cement manufacture. 9Includes asphalt fillers or extenders and mine dusting or acid water treatment. 10Includes glass manufacture and other specified uses not listed. 11Reported and estimated production without a breakdown by end use. 12Less than 1/2 unit.

COLORADO—2003 8.7 TABLE 5 COLORADO: CONSTRUCTION SAND AND GRAVEL SOLD OR USED IN 2002, BY MAJOR USE CATEGORY1

Quantity (thousand Value Unit Use metric tons) (thousands) value Concrete aggregate (including concrete sand) 6,020 $37,100 $6.15 Plaster and gunite sands 42 418 9.08 Concrete products (blocks, bricks, pipe, decorative, etc.) 238 1,610 6.78 Asphaltic concrete aggregates and other bituminous mixtures 2,580 20,800 8.08 Road base and coverings 5,470 25,900 4.73 Road stabilization (cement and lime) 56 301 5.38 Fill 1,700 7,820 4.61 Snow and ice control 67 506 7.55 Other miscellaneous uses2 210 1,700 8.11 Unspecified:3 Reported 16,800 87,600 5.23 Estimated 7,500 38,000 5.07 Total or average 40,700 222,000 5.45 1Data are rounded to no more than three significant digits, except unit value; may not add to totals shown. 2Includes railroad ballast. 3Reported and estimated production without a breakdown by end use.

TABLE 6 COLORADO: CONSTRUCTION SAND AND GRAVEL SOLD OR USED IN 2002, BY USE AND DISTRICT1

(Thousand metric tons and thousand dollars)

District 1 District 2 District 3 Use Quantity Value Quantity Value Quantity Value Concrete aggregate (including concrete sand) 563 4,340 2,230 12,700 532 3,810 Concrete products (blocks, bricks, pipe, decorative, etc.)2 30 406 W W -- -- Asphaltic concrete aggregates and road base materials3 1,750 8,540 1,660 9,110 747 4,510 Fill 363 1,620 W W W W Other miscellaneous uses4 20 197 283 1,040 32 172 Unspecified:5 Reported 5,810 30,400 4,180 21,100 351 2,830 Estimated 1,200 5,900 3,000 15,000 42 180 Total 9,740 51,500 11,300 58,700 1,710 11,500 District 4 District 5 District 6 Quantity Value Quantity Value Quantity Value Concrete aggregate (including concrete sand) 1,110 7,220 1,510 8,430 78 558 Concrete products (blocks, bricks, pipe, decorative, etc.)2 W W 101 578 W W Asphaltic concrete aggregates and road base materials3 1,210 12,200 1,820 7,430 927 5,200 Fill 337 851 618 3,740 70 450 Other miscellaneous uses4 153 1,040 237 1,900 9 68 Unspecified:5 Reported 5,830 30,000 235 1,140 351 2,060 Estimated 1,600 8,100 1,200 5,900 610 3,000 Total 10,200 59,400 5,690 29,100 2,040 11,300 W Withheld to avoid disclosing company proprietary data; included in "Other miscellaneous uses." -- Zero. 1Data are rounded to no more than three significant digits; may not add to totals shown. 2Includes plaster and gunite sands. 3Includes road and other stabilization, cement, and lime. 4 Includes railroad ballast and snow and ice control. 5Reported and estimated production without a breakdown by end use.

8.8 U.S. GEOLOGICAL SURVEY MINERALS YEARBOOK—2003